Seedlings growing very slow

[urbanfarmer]

Looks like they are not getting enough light.

This is exactly right.

In a commercial operation, the seedlings you have would be culled and discarded. They will yield poorly and/or slowly.

If you don't want to replant, you can use them (sounds like you are getting a head start on the growing season). Supplement their light with some other light, maybe a CFL or something simple. A little extra goes a long way. Add the light during normal daylight so it is an additive effect.